/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.confignode.manager.partition.heartbeat;

import org.apache.iotdb.commons.cluster.RegionStatus;
import org.apache.iotdb.confignode.manager.partition.RegionGroupStatus;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;

public class RegionGroupStatistics {

    private RegionGroupStatus regionGroupStatus;

    private final Map<Integer, RegionStatistics> regionStatisticsMap;

    public RegionGroupStatistics() {
        this.regionStatisticsMap = new ConcurrentHashMap<>();
    }

    public RegionGroupStatistics(
            RegionGroupStatus regionGroupStatus, Map<Integer, RegionStatistics> regionStatisticsMap) {
        this.regionGroupStatus = regionGroupStatus;
        this.regionStatisticsMap = regionStatisticsMap;
    }

    public RegionGroupStatus getRegionGroupStatus() {
        return regionGroupStatus;
    }

    /**
     * Get the specified Region's status
     *
     * @param dataNodeId Where the Region resides
     * @return Region's latest status if received heartbeat recently, Unknown otherwise
     */
    public RegionStatus getRegionStatus(int dataNodeId) {
        return regionStatisticsMap.containsKey(dataNodeId)
                ? regionStatisticsMap.get(dataNodeId).getRegionStatus()
                : RegionStatus.Unknown;
    }

    public Map<Integer, RegionStatistics> getRegionStatisticsMap() {
        return regionStatisticsMap;
    }

    public static RegionGroupStatistics generateDefaultRegionGroupStatistics() {
        return new RegionGroupStatistics(RegionGroupStatus.Disabled, new ConcurrentHashMap<>());
    }

    public RegionGroupStatistics deepCopy() {
        Map<Integer, RegionStatistics> deepCopyMap = new ConcurrentHashMap<>();
        regionStatisticsMap.forEach(
                (dataNodeId, regionStatistics) -> deepCopyMap.put(dataNodeId, regionStatistics.deepCopy()));
        return new RegionGroupStatistics(regionGroupStatus, deepCopyMap);
    }

    public void serialize(OutputStream stream) throws IOException {
        ReadWriteIOUtils.write(regionGroupStatus.getStatus(), stream);

        ReadWriteIOUtils.write(regionStatisticsMap.size(), stream);
        for (Map.Entry<Integer, RegionStatistics> regionStatisticsEntry :
                regionStatisticsMap.entrySet()) {
            ReadWriteIOUtils.write(regionStatisticsEntry.getKey(), stream);
            regionStatisticsEntry.getValue().serialize(stream);
        }
    }

    // Deserializer for snapshot
    public void deserialize(InputStream inputStream) throws IOException {
        this.regionGroupStatus = RegionGroupStatus.parse(ReadWriteIOUtils.readString(inputStream));

        int regionNum = ReadWriteIOUtils.readInt(inputStream);
        for (int i = 0; i < regionNum; i++) {
            int belongedDataNodeId = ReadWriteIOUtils.readInt(inputStream);
            RegionStatistics regionStatistics = new RegionStatistics();
            regionStatistics.deserialize(inputStream);
            regionStatisticsMap.put(belongedDataNodeId, regionStatistics);
        }
    }

    // Deserializer for consensus-write
    public void deserialize(ByteBuffer buffer) {
        this.regionGroupStatus = RegionGroupStatus.parse(ReadWriteIOUtils.readString(buffer));

        int regionNum = buffer.getInt();
        for (int i = 0; i < regionNum; i++) {
            int belongedDataNodeId = buffer.getInt();
            RegionStatistics regionStatistics = new RegionStatistics();
            regionStatistics.deserialize(buffer);
            regionStatisticsMap.put(belongedDataNodeId, regionStatistics);
        }
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        RegionGroupStatistics that = (RegionGroupStatistics) o;
        return regionGroupStatus == that.regionGroupStatus
                && regionStatisticsMap.equals(that.regionStatisticsMap);
    }

    @Override
    public int hashCode() {
        return Objects.hash(regionGroupStatus, regionStatisticsMap);
    }

    @Override
    public String toString() {
        return "RegionGroupStatistics{" + "regionGroupStatus=" + regionGroupStatus + '}';
    }
}
